您可以这样使用 INSERT INTO ..SELECt
：
INSERT INTO tblusers(login)SELECT CONCAt(SUBSTRINg(Familenaam, 1 ,4), SUBSTRINg(Voornaam,1,4)) FROM tblusers
如果要更新，可以执行以下操作：
UPDATe tblusers t1INNER JOIN( SELECT userid, CONCAt(SUBSTRINg(Familenaam, 1 ,4), SUBSTRINg(Voornaam,1,4)) login FROM tblusers) t2 ON t1.userid = t2.useridSET t1.login = t2.login
